loepsinger



Patented Jan. 29, 1929.

l'iED STATES ALBERT J. LOEPSINGER, OF PROVIDENCE, RI'IOIDE ISLAND.

LIQUID FUEL BURNING.

Application filed April 19, 1923.

This invention relates to liquid fuel bur11- ing apparatus. More especially it is useful for burning oil fuel, such as petroleum distillates of the order of kerosene, or less volatile oils, with the simplicity, quietness and safety which are desirable in domestic apartments.

The invention aims to do this with apparatus which is mechanically simple and is easy to maintain in efficient operating conditions.

One feature of the invention is its provision for handling the liquid fuel as and with the convenience of gaseous fuel, but without actually converting it to gaseous form. This is done by handling it as a. fog floating in air,

that is, by producing a colloidal suspension of the liquid fuel in air. Another feature is the production of this fuel fog by mechanical means, at a convenient distance from the flame, and causing its thorough distribution through its vehicle of slowly moving air,

herein called sub-primary air, in a mixture which is too rich to support combustion and which therefore is safe like illuminating gas. A further feature is the creation, by simple mechanical means, of an adequate current of the primary air of combustion, and the utilization of this current for moving the fuel laden sub-primary air to the place where the primary air is introduced, which herein is called the beginning of the burner and is preferably at the entrance into the fire box.

In one form of the invention a film of the liquid fuel is thrown centrifugally from the edge of a rotating disk against a series of adjacent stationary blades; and this is thus broken into tiny droplets which float away as a fog in the gentle current of sub-primary air. This current is produced both by the centrifugal flow of air and by suction created further along in the duct, closer to the furnace, by the ejector effect with which the primary air is introduced. The primary air is driven by the same rotating power element that generates the fog, an is conducted to annular orifices arranged to jet itinto the fog stream at the beginning of the burner, located. preferably, where the passage for fuel and air enters the fire pot of the furnace. In the burner it is reduced in cross section, to increase the flow velocity of the then combustible mixture, so as to exceed the speed of propagation of flame backward in the mixture. The fine atomization by mechanical impact, the drawing of the floating liquid particle onward by gentle auction, and the Serial No. 633,135.

handling of this and the air for supporting combustion as in dealing with gas, make it possible to work with low air pressures, and to burn the liquid substantially without noise.

The accompanying drawings show more or less diagrammatically the main features of an embodiment of the invention in a small heating plant; but it is to be understood that variations can be made, without departing from the principles herein disclosed. It is intended that the patent shall cover, by suitable expression in the appended claims, whatever features of patentable novelty exist in the disclosed invention of apparatus.

In the drawings:

The figure is an elevation, partly in section, and somewhat diagrammatic, showing a burner embodying the invention.

Referring to the drawings, 10 is a small power electric motor on whose shaft, at opposite ends, are mounted a fan 12 and a rotor disk 13 whose edge travels close to an annular series of spatter blades 14 rigidly fixed around the periphery of the rotor, interiorly of a dished casing 16 which is shown supported by the motor 10. This casing houses the rotor but the region of its peripheral edge is open into the bell shaped entrance 18 of a main duct 18 whose entrance surrounds the casing 16 at a little distance, suiiicient to form an annular passage or port 21 through which air is drawn into the duct close to the edge of the rotor and spatter plates. A gentle draft is here caused by suction induced farther along the dust by the injection therein ofthe air blast from the said fan. This blast, conducted from the fan through a pipe 22 to an annular chamber 24 surrounding the duct 18, is jetted thence through openings 26, in a conical partition 28, into the duct, in directions leading to the burner grid 30 within the firebox of the furnace. The parts describedmay be located in any convenient relation to the firebox; but the wall 32 of the latter is shown just beyond where the annular chamber 24 surrounds the main duct 18.

With the motor in operation, turning the fan and rotor, raw liquid fuel is fed by any suitable means, for which gravity is indicated in the drawing, through a drip supply pipe 34 with valve adjusted for restricted delivery to the conical hub of the rotor, from which it spreads in the form of a thin film over the rotating disk. From the periphery of the disk it is thrown by centrifugal force against the fixed blades; and by imprint therewith it tracted by the converging bell walls 18Funtil it enters the cylindrical portion 18". This slow moving current in the duct 18 has not enough air to support combustion of 1ts 18h load of liquid fuel particles. it may be regarded as analogous to a body of illuminating. gas, with the dillerence that it really is not. a gas but is a body of air in which small liquid fuelglobules are floating. Such vaporizat-ion as the liquid fuel has undergone at thisstage, if any at all, is inconsiderable and is purelyincidental. The injection of supplemental air into the fuel stream, which in the gas analogy above proposed compares with the customary introduction of primary air of combustion, occurs at the entrance of the main duct into the furnace firebox, wher the duct is somewhat enlarged having walls 28 which constitute a conical perforated partition from the primary air supply chamber 24-. This enlargement is at once'reduced by the slopingportion 18 of the wall just beyond, whose convergence increases the velocity of flow so that the speed at which the then combustible mixture enters the burner box 36 under the grid is greater than the speed of propagation of the flame backward. This control of velocity of flow prevents backfire and makes the apparatus safe from such danger.

The velocity of flow may be increased by increasing the pressure 1n the chamber24 thus causing the primary air jets to enter the current of fog at a greater speed,

it being assumed that the blower 12 is large enough to supply such air and speed as are needed.

The speed and amount of air delivered to the conduit '18 from the fan may be regulated damper 36 will; merely cause less air to be passed through the blower.

The relatively low velocity of the current issuing through the burner produces along,

"lazy and silent flame, usually rather longer than that represented in the-drawing, in

contra-distinction to the roaring flame of the forced draft type of burners. The flame burns the minute liquid droplets, without smoke, without-"noise, and with sul 'stantially complete combustion.

For certainty of attaining the described re sults in operation, the valve in pipe 3-1 may be set to deliver fuel enoughso that the airpass- 'ing in through opening 21 willbe loaded with all it cancarry of the fuel particles. If the pipe 34 delivers fuel, beyond the amount which is atomized and carried away by the rotor blades and air current, the excess drains from the sloping walls of the boiled end 18 of the conduit and may be entrapped by suitable means (not shown) and be again placed in the liquid supply.

Referring to the drawings, the motor 10, blower 12 and atomizing device 13, l l are to be considered as merely typical of any suitable variety or design of apparatus, these being each of a type which individually is al ready well known, although it should be mentioned that such atomizer has never before been used in connection with a burner or applied to liquid fuel so far as 1 am aware. But atomizers of this type are known in connection with the breaking up of water for humidifyins he. atmosphere. The atomizer used in the present invention may be madein various forms and designs such as are already known in connection with the art of producing atmospheric humidity, by increasing the water vapor content of the air; but it will be understood that such apparatus is not in the present case used as. a vaporizer. That is, it is ap plied to the breaking up of the liquid fuel mechanically to such a fine degree that althoi h still remaining as liquid it will nevertheless float in the air which is passing the atomizer; and the question of whether or not there is any appreciable evaporation of the liquid fuel or conversion thereof into its vaporous or gaseous form, does not arise. Undoubtedly combustion. It will be understood that the ratio of sizes of pipes, and of the quantity of air. introduced through 21. and 26, should be such as will cooperate to make the flame satisfactory. .These.matters can be designed by methods that. are wellunderstood. The ratio of fuelto air in the conduit 18 can be made as desired (so that the contents of the conduit have the characteristic of being by thornselves incombustible, like illuminating gas, until more air is added) by designing the port 21 so as to take inmore or less air relative to the quantity of atomized fuel produced by the atomizer, or by setting it more or less closely to the atomizer. Means for initially igniting the combustible mixture, and controls for the operation of themechanically moving parts and for the supply and drainage of fuel will ordinarily be associated with the elements depict-ed; but as such auxiliaryarrang ments arenot a partof the present invention they are omitted from the present description and drawing.

The process of the invention, which resorts tothe principle of atomizing liquid fuel by mechanical. power at a distance from the flame, that is, by breaking it into particles so small as to be capable of floating in air,

and then conveying these by flotation in rela- Cil of the floating matter notwithstanding its proximity to air and flame, has a number of important advantages. Among these are, in general, and as compared with apparatus previously proposed for burning liquid fuel, the elimination of preliminary heating for vaporizing; and of steam and compressed air blasts for atomizing the fuel; and with these the roar that accompanies combustion wherein vapor, steam or compressed air participate; also the production of flame at substantially atmospheric pressure, such small pressures as are needed for moving the air under this system and such as are generated by draft of the flame being counted as substantially atmospheric.

Inasmuch as the fuel does not meet the air which is to carry it until the body of liquid has already been dispersed, it follows that the energy for accomplishing its dispersal does not have to be carried by the air, as in those processes heretofore known where a blast of air or steam rushing past a single small opening has to disperse the solid stream of liquid which is fed thereto. Therefore the relative quantity of air can be limited to that which is needed or desired for fiotation of the dispersed fuel. Thus a perfect control of ratio of air to fuel becomes possible; and the apparatus can be designed or set so that. the slowly moving current of air has such a proportion of liquid fuel that there is not air enough to support its combustion. The insufficiency of air assures safety. The slow motion gives quietness. And the fluid ity of the mixture, coupled with its slowness of motion, permits the location of the generating apparatus at any convenient distance or direction from the fire box. It also permits of the same generating apparatus being used to serve a plurality of furnaces. And it makes simple and silent burning apparatus available for larger heaters and for burning the less volatile, or so called heavier, oils, as well as for lighter oils and for domestic heaters where the qualities mentioned are particularly important. Moreover, although electricity is here shown as a means for effecting the mechanical atomization, through the medium of the motor, the apparatus is adaptable for locations such as country houses or outlying plants where electricity, steam and compressed air are not available; for in such cases the power may be supplied by other means, as for example, by a water motor. Or, if used under a steam boiler, the apparatus can maintain itself as soon as there is enough steam to drive a small turbine in place of the electric motor herein illustrated.

I claim as my invention:

1. Apparatus for burning liquid fuel, comprising the combination, with a burner, of power driven mechanism, located at a dis tance from the burner, and adapted to receive liquid fuel and convert it into finely divided liquid particles capable of floating in slowly moving a1r; a mam air passage leading from said mechanism to the burner;

an auxiliary air passage, smaller than the main passage, opening into the main passage near the burner; and means propelling air in said auxiliary passage from behind; said propelled air being delivered into the main passage in direction toward the burner and, by suction, inducing slow motion toward the burner of air in the main passage.

2. Apparatus for burning liquid fuel, comprising the combination, with a burner, of power driven mechanism, located at a distance from the burner, whereby the liquid fuel is received and is converted into finely divided liquid particles capable of floating in slowly moving air; a main passage leading from said mechanism to the burner; an auxiliary air passage, smaller than the main passage, opening into the main passage near the burner; and means propelling air in said auxiliary passage from behind; said propelled air being delivered into the main passage in direction toward the burner and, by suction, inducing slow motion toward the burner of air in the main passage; and there being, between the junction of the two said passages and the place of the flame, a reduction in the size of the main passage, whereby velocity of flow of the combined mixture is increased to a forward speed exceeding the velocity at which the flame is propagated backward.

3. Apparatus for burnin liquid fuel comprising, in combination, a burner; a conduit leading from a distance to the burner for supplying a slow moving current of air and fuel; means at the entrance of the conduit for atomizing liquid fuel; the size of air intake opening at the entrance being so related to the operating rate of the atomizing means that the intaken quantity of atomized fuel in proportion to the intaken air makes a mixture too rich to support its own combustion.

4. Apparatus for burning liquid fuel comprising, in combination, a burner; a conduit leading to the burner from a distance for supplying a slow moving current of air and fuel; and means at the entrance for subjecting liquid fuel to mechanical shock breaking it into fine globules adapted to float in atmospheric air; said shock means being situated and arranged, with respect to said entrance, within the suction zone of the inflow of slow moving air of said current.

5. Apparatus for burning liquid fuel comprising, in combination, a burner; a conduit leading to the burner from a distance for supplying a slow moving current of,air and fuel; a multiplicity of stationary plates at the entrance of the conduit; and means for throwing liquid fuel against said plates to atomize it finely enough to float in air; said plates being arranged with respect to said entrance to permit an inflow ofair to theconduit to drawin floating atomized fuel.

6. Apparatus for burning liquid fuel comprising, in combination, a burner; a conduit thereto for a slow moving current of air and fuel; meansin annular form at the entrance of the conduit for atomizing liquid fuel so that it can float in atmospheric air; and an annular passage for intake of: atmospheric air to the conduit, leading past said annular pendent of the said air moving means and said: air current, for atomizing and floating liquid fuel in air at atmospheric pressure, located at the entrance of said conduit and within the intake zone of said current.

' 8.- Apparatus for burning liquid fuel coinprising,in combination, a burner; a conduit leading thereto; means at the conduit entrance for atomizing liquid fuel, arranged with respect to said entrance to permit the entering air to entrain the atomized fuel; and means intermediate the ends of said conduit to setup a slow-moving current of its content-s through the conduit toward the burner whereby air is drawn in at the entrance.

9. Apparatus for burning liquid fuel comprising, in combination, a burner; a conduit leading thereto having an open end entrance and having an intermediate entrance opening between said end entrance and the burner; means for forcing air through said intermediate entrance to set up a slow moving currentthrough said conduit from its end entrance; and means for atomizing liquid fuel, arrangedwith respect to said end entrance to permit air entering there to entrain the atomized fuel in proportion making a mixture too rich to support combustion; the said intermediate entrance being adopted for the air entering through it to make the whole self combustible.

10. Apparatus for burning liquid fuel comprising, in combination, means for producing a non-combustible, rich colloidal dispersal and suspension of the fuel as a liquid floating in air; a conduit leading thence to a distance for conducting said air with fuel suspended as a fog therein; and a burner to which the conduit leads.

Signed at Boston, Massachusetts, this 12th day of April, 1923.

ALBERT J LOEPSINGER. 

